1. Field of the Invention
The present invention relates to a timing cover for an engine, and more particularly to a timing cover with a high characteristic frequency band.
2. Description of the Related Art
Generally, an engine for a vehicle serves as a power generating device. The engine draws a fuel-air mixture into a combustion chamber by the operation of a suction system and a fuel system, and bums the fuel-air mixture by the operation of a combustion system, thereby generating driving force necessary to drive the vehicle.
During driving, the engine generates vibration and noise due to periodic variations in a central position according to the vertical motion of a piston and a connecting rod. Variations in inertial force are generated from the reciprocating motion of a cylinder in an axial direction. Variations in inertial force are generated from the motion of the connecting rod in the right and left direction of a crank shaft, and periodic variations in rotating force are applied to the crank shaft.
The above vibration and noise generated from the engine due to the above variations affect other peripheral components located around the engine, thereby causing other vibrations and noises. A representative one of the peripheral components is a timings cover for covering a timing belt or a timing chain interlocking a crank shaft and a cam shaft.
The timing cover is connected to one side of a cylinder block of an engine, and serves to prevent a sprocket installed on the crank shaft, a sprocket installed on the cam shaft, and a timing belt or a timing chain for interconnecting the sprockets from being exposed to the outside.
Since the conventional timing cover is connected to the cylinder block of the engine, the conventional timing cover resonates with the vibration generated by the engine. The characteristic vibration and noise generated from the driving of the timing belt or the timing chain causes another vibration and noise at a different frequency band.
The above vibration and noise generated from the timing cover deteriorate silence of the vehicle, and provide unpleasantness to passengers in the vehicle, thereby serving as a factor in reducing the comfort of passengers riding in the vehicle.
A structure in which a plurality of reinforcing ribs are formed on the inner surface of a timing cover, so that the structural rigidity of the timing cover is improved, and in which the characteristic frequency band of the timing cover can be deviated from the characteristic frequency band of the engine, has been proposed. However, the above conventional structure has only a small effect of the decrease in the vibration of the timing cover in proportion to the increase in the weight of the timing cover, thus not obtaining satisfying results.